Electric switch



Jan 6, 1931. L. A. BROWN 1,787,654

ELECTRIC SWITCH Filed March 1, 1929 3- Shoets-Sheet l L. A. BROWN ELECTRIC SWITCH Jan 6, 1931.

Filed March 1. 1929 3 Sheets-Sheet 2 1400/64 flaw/1E6? EEOW/V,

Jan 6, 1931. L. A. BROWN 5 ELECTRIC SWITCH Filed March 1. 1929 5 Sheets-Sheet 3 JQwenZOT 1401/54 flLEXH/VDEE BRO N, I

Patented Jan. 6, 1931 UNITED STATES PATENT OFFICE anaemic swrrcn Application filed larch 1, 1929. Serial No. 848,650.

This invention relates to electric switches and more particularly to a multiple break switch having a novel design whereby heavy power circuits may be made or broken with or without load thereon without arcing.

One object is to provide a switch structure in which the auxiliary contacts used to prevent arcing are entirely enclosed so as to prevent flashing or arcing. 1

Another object is to provide a structure in which the auxiliary contacts are only in closed position for a short interval during the closing and opening of the main contacts and, therefore, are prevented from heating.

In the drawings:

Figure 1 is a plan view, partly in section,

of a switch constructed in accordance with this invention.

Figure 2 is a sectional elevation taken on the line 11-11 of Figure 1, and showing the switch in open position.

Figure 3 is a similar view showing the switch in closed position. 1

Figure 4 is a. sectional end elevation taken on the line IVIV of Figure 2.

Referring more particularly to the drawings, the numerals 2 and 3 designate leads into the box 4 that encase the switch mechanism. The leads 2 and 3 are fastened to posts 5 and 6 which are secured to the insulating base 7 on the box.

The switch has two knives 8 and 9 which are pivoted by bolts 10 to supports 11 and 12, respectively, that are also mounted on the base 7.

The knives 8 and 9 have registering openings at approximately the middle oftheir length, through which a rod 13 extends and this rod is secured at its ends to the swinging end of the levers 14 and 15 which are rotatably secured in the side walls of the casing 4. The stub-shafts '14 and 15 by which the levers 14 and 15 are mounted in the side walls of the casing 4 have squared ends on which the ends of a fork 16" are secured. The fork 16 is provided with a handle 16 by which the levers 14 and 15 are swung to operate the red 13 and switch knives 8 and 9 from closed to open position and vice versa.

so Also mounted on the base 7 is an auxiliary contact mechanism by which arcing is prevented when opening and closing the switch. There is a series of stationary contacts 17 and movable contacts 18, these being mounted in holes in plates of insulating material 19, 20, 5 21, 22, 23, 24 and 25. w

The plates 19, 21, 23 and 25 are fixedly secured on the base 7 and have their abutting faces relieved to form recesses in which the plates 20-, 22 and 24 are slidably mounted.

The free or rear ends of the plates 20, 22 and 24 are spaced by spacer blocks 35 which extend rearwardly beyond the plates, and the plates and blocks are secured in assembled position by bolts 36. The projecting portions of the blocks 35 are provided with alined vertical slots 26 through which the rod 13 extends so as to provide means for reciprocating the plates 20, 22 and 24 simultaneously with the opening and closing movement of the switch knives 8 and 9. The metallic contacts 17 are arranged and located so as to be engaged by the contacts 18 when the switch is moving into and out of closed position by the slidi movement of the parts 20, 22 and 24. T e contacts 17 are connected by conductors 27 and 28 to the posts 5 and 6.

In the operation of the improved switch, the sliding contacts 18 are all in full contact with the stationary contacts 17 at the instant the knives 8 and 9 are engaged with or disengaged from the spring jaws 29 and 30, so as to prevent arcing at the instant the knives are closed or opened, andcontinued movement of the knives 8 and'9 by the handle 16 will move the contacts 18 out of engagement with the contacts 17.

When the switch is being opened. and closed, the current travels through the lead 2, the conductor 27, the engaging contacts 17 and 18 and conductor 28 to the lead 3, in this way completing a circuit through the switch. When the switch is in open pos1tion there, of course, is no current flowing through the contacts 17 and 18 because they are disengaged. When the switch is in closed position, the contacts 18 are also disengaged from the contacts 17, so that heating of the contacts is avoided. When the switch is closed the current flows through the spring connections 29 and 30 and the knives 8 and 9. It will be noted that the knives 8 and 9 are electrically connected by a bar 31.

The contacts 17 and 18, due to their being wholly enclosed, are free from flashing or arcing in the operation ofthe switch.

While I have shown and described one specific embodiment of my invention, it will be understood that I do not wish to be limited thereto, since various modifications may be made without departing from the scope thereof as defined in the appended claim.

I claim:

A multiple break electric switch comprising a base, an enclosing housing mounted around and over said base, a pair of spring contacts mounted on said base, a pair of movable knives ivotally mounted on said base and adapted to make contact with said spring contacts, auxiliary contact mechanism, said auxiliary contact mechanism comprising a plurality of stationary plates and a plurality of movable plates mounted for reciprocatory movement between said stationary plates, spacer blocks between and secured to said movable plates, said blocks extending rearwardly be ond said plates and being provided wit alined vertical slots, and means for simultaneously operating said knives and said movable plates, said means comprising a rod journaled in openings intermediate the ends of said knives and passing freely through said vertical slots in said spacer blocks, levers pivotally mounted at one end in the side walls of said housing, said rod having its ends secured to the free swinging ends of said levers, and means for swinging said levers to move said rod through an arcuate path and thereby move said knives about their pivotal mountings and said movable plates relative to said stationary plates.

In testimony whereof, I have hereunto set my hand.

LADURA ALEXANDER BROWN. 

